The IHR Earlier Medieval seminars restarted for this academic year (a mere four months ago) with Jinty Nelson talking on 'Shaping rules, making rulers: Carolingian and Abbasid inauguration-rites in comparative context', which, as usual with Jinty, made a number of subtle and fascinating points, while incidentally demonstrating some of the difficulties with comparative history in the early Middle Ages. She was focusing on the period around 750 AD when the Abbasids supplanted the Umayyad caliphate and Pippin III became the first Carolingian king of Francia. Although these events took place far apart (Jinty described it as being "about 4000 km from Soissons to Baghdad as the crow flies, but the crow never does fly") there had been contacts between Franks and Saracens since the early eighth century, and by the 760s there were embassies being sent between the two rulers. There were also shared cultural elements: monotheism, Jerusalem being seen as a holy city and David as the model war leader, worries about images in the Roman church and, more unexpectedly, a shared interest in sandal relics. (When Pippin and his wife Bertrada visited Prüm monastery in 762, there was reference to Christ's sandal as being there, while the sandal of the Prophet is a particularly well-documented Islamic relic).
Jinty's main interest was in inaugural rituals, comparisons of which are slightly hampered by the fact that the Royal Frankish Annals are probably lying about the events of 750 (as Rosamond McKitterick has demonstrated). But the continuator of Fredegar, a near contemporary source show Frankish rituals of anointing and submission by princes. The anointing (carried out by Frankish bishops, rather than the Pope) was a novelty, using the multiple religious symbolism of using holy oil in making new, healing etc. The rituals of submission, however, show continuity with the Merovingian period; in particular Jinty was arguing that Charlemagne demanding oaths of loyalty from his subjects may not have been new. She also pointed out that Bertrada was consecrated, further securing the line by excluding Pippin's brothers and nephew. Various methods of such 'dynastic slimming' became characteristic of the Carolingians – Jinty thought that Charlemagne probably killed his brother Carloman's young sons, since they don't appear later in the historical record (although, as Susan Reynolds pointed out in the discussion, there are a lot of reasons for people to die young at the period).
The Abbasids, meanwhile, were presiding over a huge empire, with central places to match: Al-Mansur allegedly built a mosque at Baghdad with room for 14,000 men, whereas Soissons church, where Pippin was anointed, measured 36x26 m. They Abbasids drew on Hellenistic, Roman and Sassanian traditions, but Andrew Marsham argues that the oath of allegiance was the key ritual and sees a tension between ideas of absolute succession and consultation/election of the ruler.
From the 860s there are oaths documented to the caliphs, and these were used to set up successors, in a system which, while it was hereditary, allowed close kin other than sons to succeed (uncles often had rights). There are interesting differences here between the (theoretical) monogamy and increasing exogamy of Frankish royal marriages and an Islamic system which had both polygamy and marriage to close cousins. Despite the Abbasid attempts to ensure the succession, there was still an element of the people's choice seen as needed and often a concern to buy off close kin with gifts.
Jinty then cited Wolfram Drews arguing that the Carolingians had more institutional ballast than the Abbasids, who suffered from a perpetual legitimacy deficit, with each caliph needing to claim a relationship to the Prophet and thus bypass his predecessors. As she pointed out, however, the Carolingians managed to take the 'dynastic slimming' a bit too far, and ended up with no legitimate adult males in 887. She ended by pointing out the word she'd never mentioned in the talk: 'coronation', and the contrast this made to late antique Rome. These weren't sacred monarchies, but all too human.
Overall, the talk confirmed the genuine advantage of a comparative approach to the early Middle Ages: it helps you see some of the other possibilities that were potentially available, but weren't taken in a particular society. It's for that reason that Chris Wickham, in particular, has stressed the need for the comparative method. But Jinty's paper was also a reminder that it's relatively rare you get such a neat line-up of subjects and sources for any early medieval topic in two different regions. There is enough commonality (and even some contact) in this case to make comparisons seem useful, especially for cultures with common Roman roots. But it's less clear how far apart you can go in chronological and spatial distance and still get interesting insights: it's something that enthusiasts for medieval world history haven't really answered effectively yet, that I know of. Comparisons aren't odorous, but they don't necessarily always give us the tool we may hope for.